1. Field of the Invention
The present invention relates to a capsule for a tooth restorative material which can be administered to a position to be restored of a patient immediately after mixing and kneading a dental restorative material constructed by two components of a powder component and a liquid component, in a filling use, a connection use, a backing use and the other intended uses for restoring the tooth in a dental treatment field, and does not generate any bursting sound at a time of starting the administration.
2. Description of the Conventional Art
Generally, the tooth restorative material is used for restoring the tooth, and, as the tooth restorative material, there has been generally used a two-component type material including a powder component and a liquid component which are reacted by mixing and kneading. Conventionally, this two-component type tooth restorative material is used by weighing the powder component and the liquid component on a scale appropriately in each case. However, in recent years, for the purpose of omitting a weighing work of the powder component and the liquid component and a work for storing the tooth restorative material after mixing and kneading in a syringe for administering it at a position to be restored, there has been developed a capsule for the tooth restorative material which stores fixed amounts of a powder component and a liquid component which have been previously weighed respectively in an isolated state, where the isolated state is cancelled at a desired time so as to be mechanically mixed and kneaded by a mixer or the like, and the mixed and kneaded material is directly extruded to administer to a position to be restored such as a cavity or the like of the tooth via a nozzle. (refer, for example, to Japanese Patent Publication No. 3-81384).
As the capsule for the tooth restorative material mentioned above, there has been used a structure in which a liquid component is stored in a bag made of a raw material obtained by laminating a resin film on an aluminum foil so as to be arranged in a state of staying with a powder component, and is reacted with the powder component by pushing and breaking the bag at a time of being used, however, there is a defect that the liquid component flowing out of the bag broken at a time of use mixes into the powder component in a state of dissolving the aluminum foil of the broken surface of the bag in the case that the liquid component is acid, and a remaining piece of the broken portion of the bag mixes into the mixed material of the powder component and the liquid component.
In order to dissolve the defect mentioned above, the applicant of the present invention has previously proposed a capsule for a tooth restorative material in which a liquid component is stored in an isolated manner in a different section from a powder component without being put into a bag, and is mixed with the powder component by pushing the liquid component into the powder component side as well as pushing and breaking a partition wall of a liquid component storing cup at a time of use, and the mixed material is administered by pushing and breaking the partition wall communicating with a nozzle (refer, for example, to Japanese Patent No. 3630738).
FIG. 6 is an explanatory sectional view showing an example of the capsule for the tooth restorative material described in Japanese Patent No. 3630738. This capsule for the tooth restorative material is constructed by a powder component storing cup 1 which is formed in a cylinder shape, has a mixing comparted chamber 1a in which a powder component A is stored, is provided with a first opening forming portion 1b to form a circular hole for an outlet of a mixed and kneaded material of the powder component A and a liquid component B on a center axis of a front end portion thereof, is provided with an applier engagement groove 1d in an outer peripheral side surface near a rear end portion, and is integrally formed by injection molding of a thermoplastic synthetic resin, a liquid component storing cup 2 which stores the liquid component B, is provided with a second opening forming portion 2b to form a circular hole for an outlet of the liquid component B on a center axis of a front end portion, is fitted into the mixing comparted chamber 1a of the powder component storing cup 1, is provided with a convex stopper 2c for preventing easily slipping into the mixing comparted chamber 1a of the powder component storing cup 1 on an outer side surface in the vicinity of a rear end portion, and is integrally formed by injection molding of a thermoplastic synthetic resin, a plunger 3 which has a rod-like projection 3a having a planar peak portion for pushing and breaking the opening forming portions 2b and 1b at a front end, is fitted into the liquid component storing cup 2, and is integrally formed by injection molding of a thermoplastic synthetic resin, a cap 5 which has a nozzle engagement port on a center axis of a front end portion, is screwed with the powder component storing cup 1 at a rear portion inner peripheral side surface thereof, and is integrally formed by injection molding of a thermoplastic synthetic resin, and a nozzle 4 which is formed in a shape capable of engaging with an outer surface of the front end portion 1c of the powder component storing cup 1 at a rear end portion 4b thereof, is fixed to the powder component storing cup 1 by the cap 5, and is integrally formed by injection molding of a thermoplastic synthetic resin.
In order to use the capsule for the tooth restorative material as mentioned above, the circular hole is opened by first pressing the plunger 3 fitted into the rear end side of the liquid component storing cup 2 which is fitted into the rear end side of the mixing comparted chamber 1a of the powder component storing cup 1 until it stops by a finger, thereby pushing and breaking the second opening forming portion 2b at the front end side of the liquid component storing cup 2 by the planer peak portion of the rod-like projection 3a of the plunger 3, and the liquid component B is completely pressed into the mixing comparted chamber 1a of the powder component storing cup 1 in which the powder component A is stored, through the opened circular hole.
Accordingly, after both the components A and B are mixed and kneaded by installing the capsule for the tooth restorative material in which the liquid component B is completely pressed into the mixing comparted chamber 1a in which the powder component A is stored, to a mixer (not shown), the plunger 3 integrated with the liquid component storing cup 2 is moved forward on the basis of pressing force of an independently provided applier (not shown) by engaging a pawl of the applier with the applier engagement groove 1d provided in the rear end portion of the powder component storing cup 1. On the basis of this operation, the first opening forming portion 1b in the front end portion of the powder component storing cup 1 is pushed and broken by the planer peak portion of the rod-like projection 3a of the plunger 3, the circular hole is opened, and the mixed and kneaded material flows into the nozzle 4 through this hole so as to be administered to the portion to be restored in the tooth.
The second opening forming portion 2b to form the circular hole on the center axis of the front end portion of the liquid component storing cup 2, and the first opening forming portion 1b to form the circular hole on the center axis of the front end portion of the powder component storing cup 1 are easily pushed and broken by the planer peak portion of the rod-like projection 3a of the plunger 3 so as to respectively open the circular holes. Then, in order to prevent wholes of the pushed and broken opening forming portions 2b and 1b from being separated from the liquid component storing cup 2 and the powder component storing cup 1 so as to mix into the mixing comparted chamber 1a of the powder component storing cup 1 and the nozzle 4, a thick portion for giving strength is provided at a part of a locally weak portion having a circular shape so that the opening forming portion is pushed and broken in a state in which one end is coupled as if hinged to each of the storing cups 2 and 1 like as a door. Further, it is necessary to have enough strength to prevent the liquid component B stored in the inner portion in an unused storage state from leaking out to the mixing comparted chamber 1a of the powder component storing cup 1 and the nozzle 4.
Accordingly, the applicant of the present invention has found that the opening forming portions 2c and 1c can be easily and securely formed by applying a punch having a thermal welding blade or a cutting blade formed in a shape coinciding with the shape of the portion to be broken to one surface at a position corresponding to the portion to be broken at least around the partition wall portion to be pushed and broken until its cutting edge comes to a depth corresponding to a predetermined thickness of the portion to be broken around the partition wall portion to be pushed and broken, in a state in which a dolly block is brought into contact with the other surface, at a time of integrally forming the opening forming portions 2b and 1b which can form the circular holes which are easily pushed and broken, in the front end portions of the liquid component storing cup 2 and the powder component storing cup 1, by injection molding of the thermoplastic synthetic resin (refer, for example, to Japanese Patent No. 4073571).
If the circular hole is opened by using the capsule for the tooth restorative material having the structure described in Japanese Patent No. 3630738 in which the opening forming portions 2b and 1b are formed in accordance with the method of Japanese Patent No. 4073571, installing the capsule in which the liquid component B is completely pressed to the mixing comparted chamber 1a storing the powder component A to the mixer so as to mix and knead both the components A and B, thereafter engaging the pawl of the independently provided applier with the applier engagement groove 1d provided in the rear end portion of the powder component storing cup 1, moving forward the plunger 3 integrated with the liquid component storing cup 2 on the basis of pressing force of the applier, and pushing and breaking the first opening forming portion 1b in the front end portion of the powder component storing cup 1 by the planer peak portion of the rod-like projection 3a of the plunger 3, the circular hole is opened in a breath in a state in which air existing together with the mixed and kneaded material of both the components A and B is compressed within the mixing comparted chamber 1a of the powder component storing cup 1. Accordingly, there is a defect that the bursting sound is generated.